1. Field of the Invention
This invention relates to gun sights and, more particularly, to telescopic gun sight apparatus usable for daytime operations and for nighttime operations.
2. Description of the Prior Art
U.S. Pat. No. 3,529,882 (Schmidt) discloses a combined day and night viewing telescope using two different optical systems for the respective viewings.
U.S. Pat. No. 3,549,231 (Scidmore et al) discloses lens systems for a day and night periscopic sight.
U.S. Pat. No. 3,712,702 (Schmidt) discloses a lens system for day and night operations. One lens system is used for day operations and a second lens system is used for night operations, with both lens systems being included in a single element.
U.S. Pat. No. 3,974,585 (Dunham) discloses gun sight apparatus for use at night. The apparatus appears to be more concerned with the structural elements than with the optical elements.
U.S. Pat. No. 4,291,479 (Lough) discloses a day and night sight mounting apparatus for a weapon. The structural elements involved are disclosed, rather than optical elements.
U.S. Pat. No. 4,764,011 (Goldstein) discloses a sighting apparatus for day and night use in which a beam splitting optical system is used.
U.S. Pat. No. 4,822,994 (Johnson et al) discloses day and night telescopic sight apparatus in which an image intensifier module for night operation is inserted between front and rear sections of a telescopic sight. The image intensifier module is removable for daytime use.
U.S. Pat. No. 4,961,278 (Johnson et al) discloses two sections of a telescopic sight, front and rear optical sections, with an image intensifier unit pivotally secured between the two optical lens units. The image intensifier unit is pivoted out of alignment for daytime operation and is pivoted into alignment for nighttime operation.
U.S. Pat. No. 5,134,798 (Lee) discloses a mounting system for two sights, one sight for day use and one sight for night use. No optics are disclosed. The mounting system structure allows two different systems to be mounted on the disclosed structure.
U.S. Pat. No. 5,5,140,151 (Weiner et al) discloses an optical system for day and night usage.
U.S. Pat. No. 5,272,514 (Dor) discloses a modular day and night gun sight apparatus. The apparatus discloses a different aiming system for day and night using a light source to assist in the aiming process.
U.S. Pat. No. 5,307,204 (Dor) discloses a mounting system for mounting a night vision system to a helmet.
In some of the above described patents, only optical systems are disclosed. In others of the above described patents, structural elements are involved. However, it will be noted that none of the above described patents disclose a relatively simple telescopic sight in which two elements, one element for day sighting and one element for night sighting, may be quickly and easily secured to a single element which may be referred to as a base telescopic sight element or housing. The apparatus of the present invention comprises three separate elements, a base telescopic sight element and two modules which may be selectively secured to the base telescopic sight module, one module for daytime sighting and the second module for nighttime sighting.